Fluid jet devices



US. Cl. 137-815 United States Patent 3,470,894 FLUID JET DEVICES RonaldRimrner, Cheltenham, England, assignor to Dowty Fuel Systems Limited,Cheltenham, England, a British company Filed June 8, 1967, Ser. No.649,068 Claims priority, application Great Britain, June 20, 1966,27,493/66 Int. Cl. F15c 1/14 5 Claims ABSTRACT OF THE DISCLOSURE A fluidjet device having a power jet nozzle and two outlet passages arranged tooperate either as a fluid switch or as a fluid amplifier, includes avortex chamber into which one outlet passage opens radially and intowhich the other outlet passage opens tangentially, the vortex chamberhaving a power outlet on its central axis.

BACKGROUND OF THE INVENTION Field of the invention Fluid switches andfluid amplifiers.

Description of the prior art In known forms of fluid switch or fluidamplifier, the deflection of a fluid jet into one or other of two outletpassages is controlled by the fluid pressure acting on opposite sides ofthe jet.

The object of the present invention is to reduce fluid energy losseswhich diminish the maximum pressure obtainable at the fluid poweroutlet.

SUMMARY The invention provides a vortex chamber into which the flow offluid from a source under pressure is controlled by a deflectable jetwhereby fluid flows either radially across the vortex chamber, or as avortex, to a fluid power outlet, while the pressure at the periphery ofthe vortex chamber is fed back to the discharge side of the jet and thusreduces the fluid pressure diflerence between the inlet and thedischarge side of the jet.

BRIEF DESCRIPTION OF THE DRAWINGS DESCRIPTION OF THE PREFERREDEMBODIMENTS In FIGURE 1, a power jet nozzle 11 opens into a switchchamber 12. Control passages 13 and 14 open through fixed restrictors 15and 16 respectively into the switch chamber 12 on opposite sides of thenozzle 11. Two outlet passages 17, 18 lead from the chamber 12 atpositions which are spaced from the nozzle 11 and which lie on oppositesides of the central axis of the nozzle. The side walls 19, 21 of theswitch chamber 12 are parallel and their separation is considerablygreater than the width of the nozzle 11. The side walls 19, 21 blendinto side wallsof the respective outlet passages 17, 18, while the otherside walls of the outlet passages are joined by a rounded jet dividersurface 22. The outlet 3,470,894 Patented Oct. 7, 1969 ice passage 17 isslightly divergent to provide pressure recovery of a fluid streamtherein, and it opens radially into a circular vortex chamber 23. Theother outlet passage 18 turns to open tangentially into the vortexchamber 23.

A circular vent 24 is formed on the central axis of the vortex chamber23 in one end wall 25, FIGURE 2. The cross-sectional area of the vent 24is less than that of the power jet nozzle 11. A fluid power outlet 26 isformed in the opposite wall 27, also on the central axis, and it has adiameter less than that of the vent 24. The power outlet 26 opens into adelivery pipe 28 for operation of a servomotor or the like, and the vent24 opens into a pipe 29 which is connected to low pressure.

The fluid jet device operates as a bi-stable switch which is controlledby a fluid pulse, or by continuously applied pressure, selectively ineither the control passage 13 or the control passage 14. Thus, a pulseor continuously applied pressure in the control passage 13 deflects ajet flowing from the nozzle 11 into the outlet passage 18, and from thistangentially into the vortex chamber 23. Due to the swirling motion ofthe fluid, the pressure falls rapidly towards the centre where the fluidis discharged with whirling motion through the vent 24. The pressure inthe smaller diameter power outlet 26 is then substantially equal to thelow pressure in the pipe 29. Fluid returned in the pipe 28 as the resultof servomotor operation may then discharge with the vortex fluid to thelow pressure pipe 29. The pressure at the periphery of the vortexchamber 23 is fed back through the passage 17 to the switch chamber 12.

A pulse, or continuously applied pressure, in the control passage 14deflects the jet flowing from the nozzle into the outlet passage 17. Thekinetic energy of the jet is partially recovered as pressure in thedivergent passage 17 and the pressure prevails without loss from theperiphery to the centre of the vortex chamber 23 since there issubstantially no rotation of fluid. The peripheral pressure is also fedback through the outlet passage 18 to the control chamber 12 wherein itreduces the pressure difference across the nozzle 11 between the fluidsource and the chamber 12. The velocity of the power jet from the nozzleis therefore low, and hence the kinetic energy losses are small. Whenthere is no rotation of fluid in the vortex chamber 23, the pressure atthe centre is at a maximum and is therefore present in the power outlet26 for operation of the servomotor or the like. The discharge area ofthe vent 24, being less than the area of the nozzle 11, is chosenwhereby there is no substantial pressure loss in the vortex chamber 23due to fluid flow through the vent 24, though the vent is not so smallas to produce a substantial pressure in the power outlet 26 when thepower jet flows into the outlet passage 18 to cause a vortex in thechamber 23.

When the power jet flows into the outlet passage 17 and the outputpressure is applied to the power outlet without any substantial flowtherethrough, a maximum pressure is available which may be up to orthereabouts of the pressure supplied to the nozzle 11.

Although the fluid switch may be operated as described by theapplication of fluid pressure to the control passage 13 or 14, it ispossible to connect each control passage to low pressure through a pilotvalve. If, for example, the pilot valve controlling the passage 13 isopened, there will be a fall of pressure on the side of the power jetadjacent to the restrictor 15 whereby the power jet is deflected intothe outlet passage 17, and remains so deflected even when the pivotvalve is closed.

In the embodiment of the invention shown in FIGURE 3, each elementhaving its counterpart in FIGURE 1 is given a like reference numeral.The arrangement differs in that a second divergent outlet passage 31from the switch chamber 12 opens radially into a second vortex chamber32 which is similar to the vortex chamber 23. A central vent 33 in thevortex chamber 32, and the vent 24 are connected to the low pressurepipe 29, while a central power outlet 34 opens into a delivery pipe 35.An interconnecting passage 36 opens tangentially at its pposite endsinto the respective vortex chambers 23 and 32.

The control of the power jet from the nozzle 11 is similar to that inthe embodiment of FIGURE 1. If, for example, the power jet enters theoutlet passage 17, the recovered pressure acts across the vortex chamber23 in the power outlet 26 and the delivery pipe 28. Fluid under pressurealso leaves the chamber 23 through the passage 36 and enters the chamber32 tangentially to induce a vortex therein. The pressure at theperiphery of the vortex is fed back through the outlet passage 31 to theswitch chamber 12 with substantially the same eflect as in FIGURE 1, butthere is low pressure, or substantially no pressure at the centre of thevortex in the central power outlet 34 and the delivery pipe 35.

Similarly, if the power jet enters the outlet passage 31, there will behigh pressure in the outlet 34 and delivery pipe 35, but little or nopressure in the power outlet 26 and delivery pipe 28. This embodimentprovides a fluid jet device with two delivery pipes suitable, forexample, for moving a double-acting piston to one end or the other of acylinder.

FIGURE 4 shows a fluid amplifier, which has a configuration generallysimilar to that of FIGURE 3, but which differs in the form of the outletpassages 41 and 42. These passages open from a chamber 43 having sidewalls 44, 45, the spacing of which at the nozzle end of the chamber doesnot greatly exceed the width of the nozzle 11. The flow divider 46formed between the passages 41 and 42 is sharp edged. The outletpassages 41 and 42 are not divergent and they do not cause attachment ofthe power jet to the side Walls 44, 45.

The power jet will, in the absence of a control signal, dividesubstantially equally between the outlet passages 41 and 42 and flowwithout rotation into the chambers 23 and 32. Since only half the powerjet flows into each chamber, the loss of fluid through the vents 24 and33 will produce a pressure at the power outlets 26 and 34 intermediatethe maximum and minimum values. The proportion of the flows in theoutlet passages 41, 42 is varied by differentially controlling thecontrol pressures in the passages 13, 14 whereby the deflection of thepower jet varies. If, for example, the flow in the outlet passage 41 isthe greater, the pressure is increased in the chamber 23 while thepressure is decreased in the chamber 32, partly due to the effect of thevents 24 and 33, and partly due to the vortex set up in the chamber 32by fluid flow through the passage 36 from the chamber 23. When the powerjet is fully deflected into the outlet passage 41, the pressure will beat a maximum in the power outlet 26 and at a minimum in the power outlet34.

In the embodiment of FIGURE 5, a fluid supply passage 51 is providedhaving branches 52, 53 which open radially into vortex chambers 54 and55 respectively. The vortex chambers have vents 56, 57 and power outlets58, 59 respectively as in FIGURES 3 and 4. A power jet nozzle 61 isconnectable with the same fluid supply and the jet flows through a fluidamplifier chamber 62 under the control of a pair of control passages 63,64 which have fixed restrictors 65 and 66 therein. The outlet passages67 and 68 from the chamber 62 enter the respective chambers 54 and 55tangentially. The nozzle 61, chamber 62, and outlet passages 67 and 68are arranged as a fluid amplifier as in FIGURE 4.

In operation, the jet when wholly deflected into the outlet passage 67,imparts rotation to fluid entering the chamber 54 from the branch supplypassage 52 so that minimum output pressure prevails at the power outlet58. There is no rotation of fluid entering the vortex chamber 55 fromthe branch passage 53 so that maximum output pressure prevails at thepower outlet 59. When the flow into the outlet passages 67 and 68 isequally divided, there is reduced rotation of fluid in the chamber 54and an equal rotation in the chamber 55. The pressures at the poweroutlets 58 and 59 are then substantially equal at a value intermediatethe minimum and maximum output pressures.

The device of FIGURE 5 can be modified by forming the nozzle 61, chamber62, and outlet passages 67, 68 to act as a fluid switch.

A further modification possible is to form the single vortex chamberdevice of FIGURE 1 as a fluid amplifier.

I claim as my invention:

1. A fluid jet device comprising (A) a power jet nozzle adapted forconnection to a source of fluid pressure,

(B) two outlet passages,

(C) pressure control means situated adjacent the nozzle and operable todeflect a power jet issuing from the nozzle into one or other of theoutlet pasages,

(D) a vortex chamber,

(E) a radial opening at the periphery of the vortex chamber which isconnected to one of said outlet passages and which is adapted to receivefluid from said source, said fluid flowing into the vortex chamberwithout rotation when the power jet is directed into said one outletpassage,

(F) a tangential opening at the periphery of the vortex chamber which isconnected to the other of said outlet passages whereby fluid flowingfrom the source forms a vortex in said chamber when the power jet isdirected into said other outlet passage,

(G) a circular vent opening to low pressure from the vortex chamber onthe central axis thereof, the vent forming a fluid flow restrictorhaving a cross-sectional area which is less than that of the power jetnozzle, and

(H) a circular power outlet also opening from the vortex chamber on thecentral axis thereof, the power outlet having a diameter less than thatof the vent, whereby when the power jet flows through the tangentialopening into the vortex chamber and fluid is discharged with whirlingmotion through the vent, the pressure in the power outlet issubstantially equal to the said low pressure, and when the power jetflows through the radial opening into the vortex chamber, the dischargeof fluid through the vent occurring substantially without rotation, thepressure in the power outlet is substantially equal to that in theradial opening.

2. A fluid jet device according to claim 1, wherein the vent and thefluid power outlet are formed in opposite end Walls of the vortexchamber.

3. A fluid jet device comprising (A) a power jet nozzle adapted forconnection to a source of fluid pressure,

(B) two outlet passages spaced from the nozzle,

(C) pressure control means situated adjacent the nozzle and operable todeflect the power jet issuing from the nozzle into one or other of theoutlet passages,

(D) a vortex chamber into which one of the outlet passages opensradially and into which the other of the outlet passages openstangentially,

(E) a circular vent opening to low pressure from the vortex chamber onthe central axis thereof, the vent forming a fluid flow restrictorhaving a cross-sectional area which is less than that of the power jetnozzle, and

(F) a circular power outlet also opening from the vortex chamber on thecentral axis thereof, the power outlet having a diameter less than thatof the vent, whereby when the power jet flows through the passageopening tangentially into the vortex chamber and fluid is dischargedwith whirling motion through the vent, the pressure in the power outletis substantially equal to the said low pressure, and when the power jetflows through the passage opening radially into the vortex chamber, thedischarge of fluid through the vent occurring substantially withoutrotation, the pressure in the power outlet is substantially equal tothat in the radially-opening passage.

4. A fluid jet device comprising (A) a power jet nozzle adapted forconnection to a source of fluid pressure,

(B) a first outlet passage and a second outlet passage both spaced fromthe nozzle,

(C) pressure control means situated adjacent the nozzle and operable todeflect the power jet issuing from the nozzle into one or other of theoutlet passages,

(D) a first vortex chamber into which the first outlet passages opensradially,

(E) a second vortex chamber into which the second outlet passage opensradially,

(F) a passage having opposite ends opening tangentially into therespective vortex chambers, and

(G) a fluid power outlet on the central axis of each vortex chamber.

5. A fluid jet device comprising (A) a power jet nozzle adapted forconnection to a source of fluid pressure,

(B) a first outlet passage and a second outlet passage both spaced fromthe nozzle,

(C) pressure control means situated adjacent the nozzle and operable todeflect the power jet issuing from the nozzle into one or other of theoutlet passages,

(D) a first vortex chamber into which the first outlet passage openstangentially,

(E) a second vortex chamber into which the second outlet passage openstangentially,

(F) a fluid pressure supply passage having branches which open radiallyinto the respective vortex chambers, and

(G) a fluid power outlet on the central axis of each vortex chamber.

References Cited UNITED STATES PATENTS 3,143,856 8/1964 Hausmann 137-815XR 3,182,676 5/1965 Bauer 137-815 3,185,166 5/1965 Horton et al 137-8153,195,303 7/1965 Widdell 137-815 XR 3,266,510 8/1966 Wadey 137-8153,267,946 8/1966 Adams et al. 137-815 3,285,265 11/1966 Boothe et al137-815 3,373,759 3/1968 Adams 137-815 SAMUEL SCOTT, Primary Examiner

